[PATCH 3.19.y-ckt 30/92] tty/serial: at91: maxburst was missing for dma transfers

[Kamal Mostafa]

3.19.8-ckt1 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: Ludovic Desroches <ludovic.desroches at atmel.com>

commit a8d4e01637902311c5643b69a5c80e2805f04054 upstream.

Maxburst was not set when doing the dma slave configuration. This value
is checked by the recently introduced xdmac. It causes an error when
doing the slave configuration and so prevents from using dma.

Signed-off-by: Ludovic Desroches <ludovic.desroches at atmel.com>
Acked-by: Nicolas Ferre <nicolas.ferre at atmel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/tty/serial/atmel_serial.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c
index 92a8b26..95f8f64 100644
--- a/drivers/tty/serial/atmel_serial.c
+++ b/drivers/tty/serial/atmel_serial.c
@@ -856,6 +856,7 @@ static int atmel_prepare_tx_dma(struct uart_port *port)
 	config.direction = DMA_MEM_TO_DEV;
 	config.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
 	config.dst_addr = port->mapbase + ATMEL_US_THR;
+	config.dst_maxburst = 1;
 
 	ret = dmaengine_slave_config(atmel_port->chan_tx,
 				     &config);
@@ -1035,6 +1036,7 @@ static int atmel_prepare_rx_dma(struct uart_port *port)
 	config.direction = DMA_DEV_TO_MEM;
 	config.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
 	config.src_addr = port->mapbase + ATMEL_US_RHR;
+	config.src_maxburst = 1;
 
 	ret = dmaengine_slave_config(atmel_port->chan_rx,
 				     &config);
-- 
1.9.1